U.S. patent application number 11/993853 was filed with the patent office on 2010-06-24 for method for controlling a coupling device between an input shaft and an output shaft.
This patent application is currently assigned to PEUGEOT CITROEN AUTOMOBILES SA. Invention is credited to Yvan Le Neindre, Gaetan Rocq.
Application Number | 20100161189 11/993853 |
Document ID | / |
Family ID | 35712952 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100161189 |
Kind Code |
A1 |
Le Neindre; Yvan ; et
al. |
June 24, 2010 |
METHOD FOR CONTROLLING A COUPLING DEVICE BETWEEN AN INPUT SHAFT AND
AN OUTPUT SHAFT
Abstract
The invention relates to a method for controlling a coupling
device between an input shaft driven by a motor and an output shaft
that can transmit a maximum torque according to the position of an
actuator of the coupling device 5 complying with a law of behavior
of the coupling means according to which: a set value (Cemb,cons)
of maximum torque to be transmitted is defined; the actual position
(Xemb,mes) of the actuator of the coupling device is measured; a
set value (Xemb,cons) is determined for actuating the coupling
device and is sent to the actuator of the coupling device, while
using a law of behavior of the coupling means obtained by
interpolation between a first law of reference of behavior of the
coupling means and at least one second law of reference of behavior
of the coupling means, and; an auto-adaptation of the law of
behavior of the coupling means is carried out for taking into
consideration its evolution resulting from the use. The method can
be used for controlling the clutch of a drive train of a motor
vehicle.
Inventors: |
Le Neindre; Yvan; (Paris,
FR) ; Rocq; Gaetan; (La Boissiere-Ecole, FR) |
Correspondence
Address: |
NICOLAS E. SECKEL;Patent Attorney
1250 Connecticut Avenue, NW Suite 700
WASHINGTON
DC
20036
US
|
Assignee: |
PEUGEOT CITROEN AUTOMOBILES
SA
Velizy Villacoublay
FR
|
Family ID: |
35712952 |
Appl. No.: |
11/993853 |
Filed: |
June 23, 2006 |
PCT Filed: |
June 23, 2006 |
PCT NO: |
PCT/FR2006/050626 |
371 Date: |
December 21, 2007 |
Current U.S.
Class: |
701/68 ; 903/914;
903/946 |
Current CPC
Class: |
F16D 2500/70264
20130101; F16D 48/06 20130101; B60K 6/387 20130101; F16D 2500/1045
20130101; F16D 2500/1066 20130101; F16D 2500/70605 20130101; F16D
2500/10412 20130101; F16D 2500/3026 20130101 |
Class at
Publication: |
701/68 ; 903/914;
903/946 |
International
Class: |
F16D 48/00 20060101
F16D048/00; G06F 19/00 20060101 G06F019/00; B60W 10/02 20060101
B60W010/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2005 |
FR |
0506513 |
Claims
1. Method for controlling a coupling device between an input shaft
driven by a motor and an output shaft that can transmit a maximum
torque based on the position of an actuator of the coupling device,
in accordance with a time-dependent law of behavior of the coupling
means, according to which, at each instant: a setpoint is defined
for maximum torque to be transmitted; the actual position of the
actuator of the coupling device is measured; using the setpoint for
maximum torque to be transmitted, the actual measurement of the
position of the actuator, and the law of behavior of the coupling
means at instant t, a setpoint is determined for the coupling
device actuator, which is sent to the coupling device actuator,
wherein: a law of behavior is used for the coupling means at
instant t, obtained by interpolating between a first reference law
of behavior for the coupling means and at least one second
reference law of behavior for the coupling means; and
self-adaptation of the interpolation result for the law of behavior
of the coupling means is performed in order to take into account
the change in the behavior of the coupling means in response to its
use.
2. Method according to claim 1, wherein the self-adaptation
procedure is performed on the interpolation result for the law of
behavior of the coupling means by integrating the difference
between the open-loop estimate of the maximum torque that the
coupling device can transmit at instant t and the closed-loop
estimate of the torque that the coupling device transmits at
instant t.
3. Method according to claim 2, wherein at least one interpolation
is performed between a first reference law and a second reference
law using an interpolation function to determine a law of
intermediate behavior at instant, which is used to determine the
law of behavior of the coupling means, and the interpolation
function is adjusted with a first gain.
4. Method according to claim 3, wherein the interpolation function
is independent of the position of the coupling device actuator.
5. Method according to claim 3, wherein the interpolation function
is dependent on the position of the coupling device actuator, the
range of variation of the position of the coupling device actuator
is divided into a plurality of intervals, and the interpolation
function is adjusted interval by interval.
6. Method according to claim 5, wherein the interpolation function
is smoothed.
7. Method according to claim 3, wherein the law of behavior at
instant t of the coupling device is equal to the law of
intermediate behavior at instant t of the coupling device.
8. Method according to claim 3, wherein the first reference law is
the law of behavior of the coupling means when it is new and cold,
and the second reference law is the law of behavior of the coupling
means when it is new and warm, an interpolation is performed
between the law of intermediate behavior at instant t a third
reference law, corresponding to the worn coupling device, using an
interpolation coefficient, and the interpolation coefficient is
adjusted by using a second gain that has an opposite sign to the
first gain and a low absolute value compared to the first gain.
9. Method according to claim 8, wherein the second interpolation
coefficient is adjusted continuously throughout the life of the
coupling device, and the first coupling coefficient is adjusted
each use period of the device by reinitializing it at the beginning
of each use period.
10. Method according to claim 1, wherein the coupling device is a
controlled clutch.
11. Method according to claim 1, wherein the coupling device is
incorporated into a traction drive of a motor vehicle.
12. Coupling device between an input shaft and an output shaft,
such as a clutch, including a control means, wherein the control
means is appropriate for implementing the method according to claim
1.
13. Coupling device according to claim 12, which is incorporated
into the traction drive of a motor vehicle.
14. Method according to claim 1, wherein the coupling device is
incorporated into a hybrid traction drive of a motor vehicle.
Description
[0001] The present invention relates to the control of a coupling
device between an input shaft driven by a motor and an output shaft
that can transmit a maximum torque based on the position of an
actuator of the coupling device, in accordance with a law of
behavior of the coupling means.
[0002] A hybrid traction drive--for example, composed of a heat
engine coupled to an electrical machine via a clutch, and which
drives an input shaft of a gearbox, which itself drives the wheels
of a motor vehicle--must have torque control for the engine
members, i.e., the heat engine and the electrical machine, in order
to best meet the driver's demand, expressed in terms of torques to
apply at the wheel.
[0003] In a hybrid traction drive, the torque to apply at the wheel
is distributed between the heat engine and the electrical machine
based on the specific operating conditions of the vehicle, in
particular to optimize the energy consumption of the traction
drive.
[0004] In order to control this assembly, the distribution of
torque must be varied between the heat engine and the electrical
machine. This entails being able to couple and decouple the heat
engine and the electrical machine with a coupling means between the
heat engine and the electrical machine. This coupling member, which
is generally a friction clutch, must be controlled in such a way
that the torque transmitted by the clutch is precisely ascertained,
at least during periods when the clutch is sliding.
[0005] Conventional traction drives also have coupling/decoupling
means that can be controlled. When the coupling/decoupling means
are controlled, the transmitted torque must also be controlled,
particularly upon starting or changing gearbox ratios.
[0006] In order to properly control such a device, one must
precisely formulate a clutch operation law that can determine the
relation between the position of an actuator of the clutch and the
maximum torque that the clutch can transmit during the time it is
sliding.
[0007] This is why control devices for such traction drives use a
law of behavior for the clutch that yields the relation between the
position of the clutch command member and the maximum torque that
said clutch can transmit. But such laws are progressive over time
for various reasons, particularly because the clutch heats up when
it is used frequently, or because of wear on it or deviations in
manufacturing characteristics.
[0008] The progression in the laws of behavior of the clutch are
taken into account by establishing procedures to determine the
biting point in particular: that is, the position of the command
member that allows contact to begin between the two clutch
plates.
[0009] However, this approach has the drawback of being rather
imprecise. Particularly, it is observed that the procedure for
determining the biting point is highly sensitive. For this reason,
in actual vehicle use, using such a procedure leads to unacceptably
rough operation, with the result that it is preferable to retain
laws of clutch behavior without factoring in the variations in the
biting point. However, it is observed that the clutch control is
highly irregular with this approach as well.
[0010] The purpose of the present invention is to remedy this
difficulty by proposing a means for adjusting the laws of clutch
behavior based on clutch use so as to obtain the best possible
modeling of clutch behavior at each instant in order to attain good
control of the clutch.
[0011] To this end, the object of the invention is a control method
for a coupling device between an input shaft driven by a motor and
an output shaft that can transmit a maximum torque based on the
position of an actuator of the coupling device, in accordance with
a time-dependent law of behavior for the coupling means that
relates the value of the maximum transmittable torque to the value
of the position of the coupling means actuator, according to which
at each instant: [0012] a setpoint is defined for maximum torque to
be transmitted; [0013] the actual position of the actuator of the
coupling device is measured; [0014] using the setpoint for maximum
torque to be transmitted, the measurement of the actual position of
the actuator, and the law of behavior of the coupling device at the
instant under consideration, a setpoint is determined for the
coupling device actuator, which is sent to the coupling device
actuator.
[0015] In order to implement this method: [0016] at each instant, a
law of behavior is used for the coupling means, which is obtained
by interpolating between a first reference law of behavior for the
coupling means and at least one second reference law of behavior
for the coupling means, and [0017] self-adaptation of the
interpolation result for the law of behavior of the coupling means
is performed in order to take into account the change in the
behavior of the coupling means in response to its use.
[0018] Preferably, the self-adaptation procedure is performed on
the interpolation result for the law of behavior of the coupling
means using an integration with respect to the length of time
between open-loop estimation of the maximum torque that the
coupling device can transmit at each instant and closed-loop
estimation of the torque that the coupling device transmits at each
instant.
[0019] By preference, at least one interpolation is performed
between a first reference law and a second reference law using an
interpolation function a to determine a law of intermediate
behavior at each instant, and the interpolation function is
adjusted with a first gain K.alpha..
[0020] The interpolation function can be independent of the
position of the coupling device actuator.
[0021] The interpolation function can also be dependent on the
position of the coupling device actuator, and the range of
variation of the position of the coupling device actuator is
divided into a plurality of intervals, with the interpolation
function being adjusted interval by interval. In addition, the
interpolation function is smoothed.
[0022] By preference, the law of behavior at each instant for the
coupling device is equal to the law of intermediate behavior at
each instant for the coupling device.
[0023] For example, the first reference law is the law of behavior
of the coupling means when it is new and cold, and the second
reference law is the law of behavior of the coupling means when it
is new and warm.
[0024] In addition, we interpolate between the law of intermediate
behavior and a third reference law, corresponding to the worn
coupling device, using an interpolation coefficient .beta., which
is adjusted by using a second gain K.beta. that has an opposite
sign to the first gain K.alpha., and a low absolute value compared
to the first gain.
[0025] By preference, the second interpolation coefficient .beta.
is adjusted continuously throughout the life of the coupling
device, and the first coupling coefficient is adjusted each use
period of the device by reinitializing it at the beginning of each
use period.
[0026] The coupling device is a controlled clutch, for example, and
it can be incorporated into a traction drive, particularly a hybrid
traction drive of a motor vehicle.
[0027] The invention also concerns a coupling device comprising the
appropriate control means for implementing the method according to
the invention. For example, the coupling device is incorporated
into the traction drive of a motor vehicle.
[0028] The invention will now be described more precisely, but not
exhaustively, with reference to the annexed figures, in which:
[0029] FIG. 1 is a schematic diagram of a clutch control;
[0030] FIG. 2 is a schematic view of the double interpolation
principle used in a method for controlling a clutch;
[0031] FIG. 3 is a schematic representation of the interpolation
functions used in a method for controlling a clutch; and
[0032] FIG. 4 is a schematic representation of the interpolation
functions used for controlling a clutch after a certain period of
use.
[0033] To control the controllable clutch 1, a control device is
used, generally referenced 2, which transmits to the clutch a
position setpoint of the clutch control device Xemb,cons. This
clutch control device 2 receives an input torque setpoint for the
clutch Cemb,cons. To determine the position setpoint Xemb,cons for
the clutch control means, the clutch control device 2 has a first
loop, called a "closed loop", that can estimate the torque actually
transmitted by the clutch when it is operating in sliding mode,
based on a measurement of the actual position of the clutch
actuator Xemb,mes and measurements of motor torque Cmot and motor
speed Wmot of the drive motor for the input torque of the clutch
input shaft; this estimator yields a quantity Cemb,bf that is
compared to the clutch setpoint provided by the traction drive
control system. Such an estimator is known in itself to those
skilled in the art, and uses a dynamic behavior model for the
traction drive.
[0034] The torque setpoint for the clutch Cemb,cons and the
closed-loop estimate of the torque actually transmitted by the
clutch Cemb,bf are compared in a first comparator 4 that calculates
the difference between these two torques. This difference is input
to a module that computes a control torque Cemb,r, which is the
torque setpoint that will be used to determine the position
setpoint for adjusting the clutch control means. Such a computing
module for the control torque is known in itself to those skilled
in the art.
[0035] The control torque Cemb,r is converted by a module 6 to a
position setpoint for the clutch actuator Xemb,cons. The module 6
uses a law of behavior for the clutch at instant t Cemb(Xemb; t)
that determines the relation between the maximum torque
transmittable by the clutch and the position of the control
member.
[0036] The actuator position setpoint Xemb,cons is sent to a
dynamic clutch modeling module 7 that takes into account the
positioning dynamics of the clutch actuation means, and
consequently the time gaps, to determine the theoretical position
of the clutch command member at instant t. This value is then
converted, by a module 6' that uses the same law of behavior as
module 6, to an open-loop estimate Cemb,bo of the maximum torque
that the clutch could transmit at instant t.
[0037] Note that in the closed loop, the measured actual clutch
position Xemb,mes is converted to a torque estimate Cemb,mes by a
module 6'' that uses the same law of clutch behavior.
[0038] Note also that the three laws of clutch behavior 6, 6' and
6'' are identical at instant t.
[0039] In order to take into account changes over time in the
clutch behavior, the law used by modules 6, 6' and 6'' is adjusted
using a self-adaptation procedure that factors in a result from a
comparator 8 comparing the open-loop estimate Cemb,bo of the
maximum torque that the clutch can transmit at instant t and the
closed-loop estimate of the torque actually transmitted by the
clutch at instant t Cemb,bf. The difference between these open-loop
and closed-loop estimates of the torque transmittable vs.
transmitted by the clutch is used to adjust the laws of clutch
behavior in a self-adaptation module 9 that performs operations
such as integration, using gains that can be adjusted based on the
desired adaptation behavior.
[0040] The self-adaptation process used to adjust the formulation
of the laws of clutch behavior will now be described.
[0041] First, referring to FIG. 2, we will define the various laws
of clutch behavior to be used.
[0042] First, we consider a first law of behavior Cemb1 (Xemb),
which is the law of behavior for the clutch when it is new and
cold: that is, when the linings are not worn or heated up from
being in use. We also consider a second law of clutch behavior
Cemb2(Xemb), which corresponds to the behavior of the new clutch
when warm: i.e., the new clutch when it has been in use and is at
its maximum temperature in use. These two curves are offset from
one another because of the expansions occasioned by the clutch
heating up. By using a time-dependent interpolation function
.alpha., which can either be a coefficient or which can depend on
the position Xemb of the clutch actuator (or command member), we
can determine the law of behavior for the clutch in new condition
at a given instant t, i.e., at a certain temperature that depends
on the conditions in which the clutch is used. This intermediate
law Cembint, (Xemb,t) corresponds to the law of behavior for the
clutch in new condition in the actual operating conditions. This
law can be written as: Cembint (Xemb,t)=.alpha.(Xemb,t).times.Cemb1
(Xemb)+[1-.alpha.(Xemb,t)].times.Cemb2(Xemb).
[0043] In this formula, .alpha.(Xemb, t) is expressed very broadly
as a function of Xemb. The person skilled in the trade will
understand that this function can be constant while Xemb varies. In
this case, .alpha. is a constant that is simply time-dependent.
[0044] Lastly, we use a third law Cemb3(Xemb), which corresponds to
the law of behavior for the clutch when it is worn, and which is
offset from the other laws, in particular due to wear on the clutch
linings, which thus modifies the clutch geometry. This law is
characterized by the fact that the point of contact of the two
clutch plates is substantially displaced relative to where it is
when the clutch is new. Furthermore, the stiffness of the control
mechanism and the characteristics of the friction materials
gradually change over the life of the clutch.
[0045] In order to represent the actual law of clutch behavior to
be used at an instant t, which corresponds to actual operating
conditions of the clutch and its state of wear, we use a law
Cemb(Xemb,t) obtained by interpolating between the law of
intermediate clutch behavior and the law of behavior for the worn
clutch. To perform this interpolation, we use an interpolation
coefficient .beta. such that at a maximum torque transmittable by
the given clutch, the position Xemb of the actual clutch control
means is obtained by linear interpolation between the position
setpoints of the clutch control means a) when the clutch is
completely worn and b) when the clutch is following the law of
intermediate behavior as it has just been defined.
[0046] If Xembint (Cemb,t) is the actuator position defined by the
intermediate law valid at instant t to obtain a maximum
transmittable torque Cemb, Xemb3 (Cemb) is the actuator position
defined by the law corresponding to the completely worn clutch,
from which we can obtain the same torque, and Xemb (Cemb,t) is the
position that must be assigned to the actuator at instant t in
order to obtain the torque Cemb, with heating of and wear on the
clutch taken into account, then we have:
Xemb(Cemb,t)=.beta.Xemb,int(Cemb,t)+(1-.beta.)Xemb3(Cemb).
[0047] In light of these different characteristics of the laws of
clutch behavior and of the theoretical laws in new-cold, new-warm
and worn condition, it appears that by comparing the open-loop
setpoint for maximum torque transmitted by the clutch Cemb,bo with
the closed-loop estimate of the torque actually transmitted by the
clutch Cemb,bf, we can estimate how the interpolations between the
various theoretical laws of clutch behavior must vary over
time.
[0048] In particular, if the closed-loop torque estimate is higher
than the open-loop torque estimate, this means that in the
interpolation that involves the law of behavior for the
new-condition, cold clutch and the law of behavior for the
new-condition, warm clutch, gives too much weight to the law of
behavior for the new-condition, cold clutch. Given these
conditions, it is advisable to decrease the value of the
interpolation function .alpha..
[0049] Actually, the open-loop torque estimate corresponds to the
value calculated from the estimated law of clutch behavior, and the
closed-loop estimate is close to the actual torque. For this
reason, when the closed-loop estimate is higher than the open-loop
estimate, we can conclude that the estimated law of clutch behavior
underestimates the torque transmitted by the clutch.
[0050] In the example under consideration, at given clutch actuator
position, the torque calculated for the cold clutch is less than
the torque calculated for the warm clutch. Under these conditions,
if the function .alpha. is too high, the estimated law of clutch
behavior underestimates the torque transmitted.
[0051] For this reason, in the case of the example, when the
estimated open-loop torque is less than the estimated closed-loop
torque, this means that the function .alpha. is too high.
[0052] Conversely, if the closed-loop torque estimate is less than
the open-loop torque estimate, it is advisable to update the
interpolation function a in the other direction.
[0053] Note that the directions of change indicated here can depend
on the way the clutch is built and the way it operates. The person
skilled in the art knows how to adjust for all of the specific
cases.
[0054] Thus, in order to adjust the law of behavior, a procedure
for adjusting the interpolation function .alpha. is introduced into
the control system, which consists of updating this function so
that the derivative with respect to time of the value of the
function .alpha. is proportional to the difference observed between
the closed-loop torque estimate and the open-loop torque estimate.
The proportionality coefficient is a gain K.sub..alpha..
[0055] Such an adjustment--which we will come back to later--has
the advantage that it takes into account clutch heating processes:
i.e., the processes that occur during a period of clutch use; but
it has the disadvantage of not taking wear and tear processes into
account.
[0056] Wear and tear processes are taken into account by adjusting
the coefficient .beta. of the second interpolation described above.
Arguments similar to those given for adjusting the coefficient
.alpha. show that the coefficient .beta. must be adjusted as a
function of the difference between the closed-loop torque estimate
and the open-loop torque estimate, inversely to the .alpha.
function adjustment, and with a much lower rate of adjustment.
Thus, to adjust the coefficient .beta., we use a law such that the
derivative of the coefficient .beta. with respect to time is
proportional to the difference observed between the closed-loop
torque estimate and the open-loop torque estimate, with a
proportionality coefficient, or gain K.sub..beta., that is much
smaller in absolute value than the coefficient K.sub..alpha., and
is opposite in sign to the coefficient K.sub..alpha.. Combining
these two adjustments yields a behavior curve Cemb(Xemb, t) that
takes into account both clutch heating and wear.
[0057] Given that clutch heating is a variable process that occurs
only during periods of clutch use and disappears when the clutch is
left for a certain time at rest, and that the wear and tear process
is an ongoing process, the interpolation function .alpha. and the
interpolation coefficient .beta. adjustments are different.
[0058] In particular, the interpolation results using the
interpolation function .alpha. are zeroed out after each period
where the clutch is not in use for a long enough time that its
temperature returns to normal. In contrast, the coefficient .beta.
adjustments are cumulative over the life of the clutch.
[0059] Proceeding in this manner, we obtain clutch behavior curves
that are self-adapted, based not only on instantaneous clutch use,
but also on prior use. For this reason, this approach yields a
clutch control law that corresponds to the actual state of the
clutch at the moment it is used.
[0060] As previously indicated, the interpolation between the law
of intermediate clutch behavior and the law of clutch behavior when
it is completely worn out is performed with a single interpolation
coefficient .beta.. In contrast, interpolating between a law of
behavior for the new clutch and a law of behavior for the heated
clutch is preferably done with an interpolation that is not
constant over the entire range of operation of the clutch, but is
performed operating interval by clutch operating interval, as will
now be explained; and for this reason, instead of an interpolation
coefficient, we use an interpolation function .alpha.(Xemb, t),
which not only varies over time like the coefficient .beta., but
which additionally depends on the position Xemb of the clutch
control member.
[0061] As shown in FIG. 3, to achieve this, we divide the position
variation range of the clutch control means Xemb into a certain
number of segments, e.g. six segments, as indicated in the figure:
a first segment I1 spanning the interval between 0 and 10%, a
second segment 12 centered on 20%, which corresponds to the
interval between 10 and 30%, an interval 13 centered on 40%, an
interval I.sub.4 centered on 60%, an interval I.sub.5 centered on
80%, and an interval I.sub.6 that goes from 90 to 100%. For each of
these intervals, we can define an interpolation coefficient:
.alpha.0 for the first interval, .alpha.20 for the second interval,
.alpha.40 for the third interval, .alpha.60 for the fourth,
.alpha.80 for the fifth, and .alpha.100 for the last interval. We
also define smoothing functions, shown in FIG. 3, corresponding to
each of the intervals, such that the sum of these smoothing
functions for any setpoint of the clutch control means is equal to
1. These functions are called L.sub.1(Xemb), L.sub.2(Xemb),
L.sub.3(Xemb), L.sub.4(Xemb), L.sub.5(Xemb), and L.sub.6(Xemb),
respectively. Each smoothing function results in a weighting across
the interval I.sub.x to which it is applied, and across the
adjacent intervals I.sub.x-1 and I.sub.x+1, thereby providing a
smoothing function. Then we define the global interpolation
function a(Xemb), equal to the sum of the products of the
interpolation coefficients and the smoothing functions for the
corresponding intervals:
.alpha.(Xemb)=.alpha.0.times.L1(Xemb)+.alpha.20.times.L2(Xemb)+ . .
. +.alpha.100.times.L6(Xemb).
[0062] To perform the adjustment, at each instant t, we determine
which operating interval the clutch is in, and we adjust the
coefficient .alpha.i for the corresponding interval. Over the life
of the clutch, we thus adjust the various interpolation
coefficients interval by interval and introduce them into the
formula that defines the interpolation function, which makes it
possible to adjust this interpolation function. This segment
interpolation is done only for the coefficient .alpha., which takes
into account the clutch heating factor. The heating process does
indeed have effects that are a function of the clutch operating
range. Using these smoothing functions as described has the
advantage of preventing this self-adaptation by segments from
producing fluctuations when updating the calculated clutch behavior
law, which could lead to problems with clutch control. In
particular, this smoothing prevents non-monotonicities in the law
of clutch behavior, which would produce impossible reversals.
[0063] FIG. 4 gives an example of the interpolation curves after
some adjustment, and as we can see, the interpolation coefficients
.alpha.0, .alpha.20, .alpha.40, .alpha.60, etc., have changed
substantially relative to the initialization value, which was 0.5,
with the result that the weight of each of the smoothing laws has
changed significantly, which yields the smoothed interpolation
function shown in FIG. 4.
[0064] The self-adaptation method that has just been described
takes into account two interpolations, one corresponding to clutch
heating and the other to wear and tear. In addition, one of the
interpolations is complex, since it is performed by segment. But
simpler self-adaptations can be done, e.g., by performing just one
interpolation and using one law for the new, heated clutch and the
worn clutch, and/or by not segmenting one of the
interpolations.
[0065] This method can be implemented by a control device that
includes a computer suitable for controlling a coupling/decoupling
device such as a clutch in a traction drive, e.g. for a vehicle, in
particular a motor vehicle.
* * * * *